1. Field of the Invention
This invention relates to methods and systems for asynchronously testing and carrying out procedures on magnetic disk drives.
2. Description of the Prior Art and Related Information
FIG. 1 shows the principal components of a magnetic disk drive 100 such as may be tested by the asynchronous disk drive testing system and according to the methods of the present invention. With reference to FIG. 1, the disk drive 100 comprises a head disk assembly (HDA) 144 and a printed circuit board assembly (PCBA) 114. The HDA 144 includes a disk drive enclosure comprising base 116 and a cover 117 attached to the base 116 that collectively house a disk stack 123 that includes one or a plurality of magnetic disks (of which only a first disk 111 and a second disk 112 are shown), a spindle motor 113 attached to the base 116 for rotating the disk stack 123, an HSA 120, and a pivot bearing cartridge 184 that rotatably supports the head stack assembly (HSA) 120 on the base 116. The spindle motor 113 rotates the disk stack 123 at a constant angular velocity. The HSA 120 comprises a swing-type or rotary actuator assembly 130, at least one head gimbal assembly (HGA) 110, and a flex circuit cable assembly 180. The rotary actuator assembly 130 includes a body portion 140, at least one actuator arm 160 cantilevered from the body portion 140, and a coil portion 150 cantilevered from the body portion 140 in an opposite direction from the actuator arm 160. The actuator arm 160 supports the HGA 110 that, in turn, supports the slider(s). The flex cable assembly 180 may include a flex circuit cable and a flex clamp 159. The HSA 120 is pivotally secured to the base 116 via the pivot-bearing cartridge 184 so that the slider at the distal end of the HGA 110 may be moved over the surfaces of the disks 111, 112. The pivot-bearing cartridge 184 enables the HSA 120 to pivot about a pivot axis, shown in FIG. 1 at reference numeral 182. The storage capacity of the HDA 144 may be increased by, for example, increasing the track density (the TPI) on the disks 111, 112 and/or by including additional disks in the disk stack 123 and by an HSA 120 having a vertical stack of HGAs 110 supported by multiple actuator arms 160.
The “rotary” or “swing-type” actuator assembly comprises a body portion 140 that rotates on the pivot bearing 184 cartridge between limited positions, a coil portion 150 that extends from one side of the body portion 140 to interact with one or more permanent magnets 192 mounted to back irons 170, 172 to form the voice coil motor (VCM), and the actuator arm 160 that supports the HGA 110. The VCM causes the HSA 120 to pivot about the actuator pivot axis 182 to cause the slider and the read write transducers thereof to sweep radially over the disk(s) 111, 112.
After the HDA 144 and the PCBA 114 are mated, the disk drive must undergo a variety of tests and procedures to configure and validate the proper operation of the disk drive. Such testing conventionally is carried out in a “single plug tester”, which is a test platform that includes a bank of slots into which the disk drives are manually loaded and unloaded. A sequential series of tests and procedures are then carried out on the loaded disk drives. Some of the test and procedures are subject to strict environmental control requirements. Conventionally, the drives remain in the same slot during the administration of the entire sequence of tests, and are removed in batch only at the conclusion of the sequence of tests.
It may be appreciated, however, that such a test platform architecture may lead to inefficiencies. Some of these inefficiencies are organic to the structure of the test platform and to its batch mode of operation, while other inefficiencies stem from various evolutionary changes in the disk drives themselves. At the outset, the batch mode of operation of single plug testers limit the platform's throughput to the time required for the slowest drive to complete the prescribed sequential series of tests. Drives that may complete the sequential series faster than other (for whatever reason) or fail any test must sit idle and occupy a slot that would otherwise be available for the administration of tests to another disk drive. Some evolutionary changes of the disk drives themselves that affect the operation of conventional test platforms include the ongoing transition from drives having a parallel interface (e.g., EIDE drives) to drives having a serial interface (such as Serial Advanced Technology Architecture or SATA). However, even during this transition to serial drives, there remains a non-negligible demand for drives having a parallel interface. Therefore, from a manufacturing point of view, both parallel and serial drives must continue to be manufactured, at least during this period of transition. Moreover, the capacities of such drives can vary over a wide range. For example, if drives are based upon an 80 Gbyte platter, then 80 Gbyte drives, 160 Gbyte and 240 Gbyte drives may be produced, possibly along with other capacities. To complicate matters, the time required for defect mapping and administration (which operations are carried out in the test platform) is directly proportional to the density of the drive, rendering the batch operation of conventional testers problematic if drives of different capacities are to be processed simultaneously. It is apparent, therefore, that disk drive manufacturers are faced with manufacturing a wide variety of disk drives of different capacities and interfaces. The testing and validation of such a wide variety of drives using conventional single plug testers is burdensome and costly.
From the foregoing, it may be appreciated that new test systems and methods are needed. In particular, what are needed are methods and systems for testing a plurality of drives that do not suffer from the inefficiencies of conventional test platforms and that allow the simultaneous testing of drives having a range of interfaces and capacities. As drive testers represent large capital expenditures for disk drive manufacturers, a more efficient tester increases throughput, lowers costs and may allow manufacturers to use a reduced-footprint test platform, which further saves costly factory floor space.